Laws of Palamecia

You may be looking for the ability of the same name from the ability card The Blank.

The Laws of Palamecia are the set of governing rules for the mechanics of the world, as enforced by the System of Palamecia. The laws are many, and not all of them are actually known by the people of Palamecia, or even by the Echo fairies. Blanks and other prospective Warriors of Light are expected to follow these laws. Some Laws can be bent, and some broken, but they are largely the way the world works, rather than being rules that people should live by.

The main proponent of the Laws is Vox, who introduces Blanks to the world and acts as a self-appointed overseer.

None shall remember the names of those who do not fight.
Fighting is a necessary aspect of the System of Palamecia. Those who do not fight are either killed by those that do, or they never rise above the obscurity of the common people.

Those who do not follow the laws will be branded as heretics.
Palamecia is very particular about its heroes, even going so far as to suggest there is only a single chosen one. Blanks are expected to try to follow the path for the Warrior of Light. If a person is found to be outside the System -- either because they started there, or because they openly disregard the Laws -- they are marked by the System as heretics. Vox compels Blanks and others to kill them when they're around.

The Warrior of Light will follow the Prophecy.
There are a lot of statements and recordings that dictate not just what the Warrior of Light MUST do, but presage aspects of his journey. One result is a feeling that all of Wol's journey has been foretold, and he cannot escape it.

Many are the trials along the Warrior's path.
Narrated in greater detail in The Prophecy, prospective Warriors of Light are constantly tested along their path with trials that they must face and conquer before they can continue. Requirements for these trials vary from outright strength, to precision, to the ability to solve puzzles. Attempts to avoid these trials are usually futile -- the world will inevitably steer the Warrior back to the trial from all other paths.

The battles find those willing to fight.
Many come to Palamecia, by design or by accident. Some, like Garland, reject the laws and refuse to play along. Some, like Cloud, Lightning and Tidus, are caught in events that have no place for them. In each case, battles come along that are specifically meant for the Warrior of Light -- others are not allowed to participate, and will be forcibly rebuffed if they try.

Chaos will return.
The System of Palamecia is designed to work in a repeated, endless cycle. Chaos comes, bringing despair. A Warrior of Light rises, and vanquishes Chaos. The Warrior of Light then leaves for other realms. The System then regenerates Chaos for the next Warrior of Light to confront.

After Wol successfully takes down Chaos, he is offered the option to move on, which he refuses. Echo notes that Chaos will simply come back again if the System is left as-is, requiring Wol to do it all over again. It is only because Wol breaks the System that Chaos is stopped from returning.